Latch for microwave oven

ABSTRACT

A door latch assembly for a microwave oven having a latch plate mounted on the microwave oven door, said oven also including means on the front face of the oven for receiving the latch. A switch holder or plate assembly and an actuable slide bar are disposed behind the face wall of the oven. The switch holder assembly is basically stationary whereas the slide bar is actuable by means of an actuating bar or button accessible on the front side of the face wall of the oven. For engagement with each latch, there is provided a latch receiving element which is pivotally supported intermediate the switch holder assembly and the actuating slide bar so that when the oven door is closed and the slide bar is actuated against its normally upwardly biased position the latch receiving element pivotally disengages from the latch and the door is permitted to open. A separate opening bias means may be provided.

United States Patent 11 1 Robinson [4 1 Feb. 11,1975

1 1 LATCH FOR MICROWAVE OVEN [75] lnventor: Donald B. Robinson,Framingham,

Mass.

22 Filed: May 23,1974

21 Appl. No.: 472,544

[52] US. Cl 126/197, 126/191, 292/48,

292/D1G. 69, 219/413 [51] Int. Cl. F23m 7/00 [58] Field 01 Search126/190, 191, 197, 192,

126/198; 292/47, 48, 221, 222,223, 53, DIG. 69; 219/412, 413

Primary E.\'aminerCarroll B. Dority, .lr. Assistant Examiner-Larry l.Schwartz Attorney, Agent, or Firm-Wolf, Greenfield & Sacks [57] ABSTRACTA door latch assembly for a microwave oven having a latch plate mountedon the microwave oven door. said oven also including means on the frontface of the oven for receiving the latch. A switch holder or plateassembly and an actuable slide bar are disposed behind the face wall ofthe oven. The switch holder assembly is basically stationary whereas theslide bar is actuable by means of an actuating bar or button accessibleon the front side of the face wall of the oven. For engagement with eachlatch, there is provided a latch receiving element which is pivotallysupported intermediate the switch holder assembly and the actuatingslide bar so that when the oven door is closed and the slide bar isactuated against its normally upwardly biased position the latchreceiving element pivotally disengages from the latch and the door ispermitted to open. A separate opening bias means may be provided.

10 Claims, 3 Drawing Figures PATENTEB FEB] I 1975 SHEET 10F 3 PMENTEDFEB] 1 I975 SHEET 2 OF I 3 1 LATCH FOR MICROWAVE OVEN BACKGROUND OF THEINVENTION The present invention relates to a novel latching mechanismfor use with a microwave cooking oven.

One object of the present invention is to provide an improved latchingmechanism for a microwave cooking oven.

Another object of the present invention is to provide a latchingmechanism that preferably employs at least two latches each preferablyhaving a switch means associated therewith. It is also a purpose of thepresent invention to provide a further switch associated with the meansfor biasing the door to an open position. 7

Another object of the present invention is to provide a latchingmechanism readily adjustable so that the door can be secured in itsclosed position with varying degrees of tightness. After some use of theoven this adjusting means can also be used to readjust the door so thatit is maintained tightly closed when in the closed position.

SUMMARY OF THE INVENTION To accomplish the foregoing and other objectsof this invention there is provided a latch assembly for securing amicrowave oven door to the face of the microwave oven. This assemblygenerally comprises a part that is affixed to the door and a second partfor engagement with the first part and that is disposed behind the faceof the oven. The means that are fastened to the cantilevered end of theoven door include at least one latch. The face of the microwave oven hasat least one aperture to receive this latch. Disposed on the backside ofthe face of the microwave oven is a latch receiving means which includesmeans defining an edge for engagement with the latch when the door isclosed. This latch receiving means is pivotally supported with the edgedisposed intermediate the oven face and the pivot point. The latchassembly further comprises a sliding element arranged to move in agenerally vertical direction and means freely securing the latchreceiving means to the sliding element so that as the sliding elementmoves the latch receiving means is free to pivot about the pivot point.The sliding element is biased to a position wherein the latch and thelatch receiving edge are in engagement when the door is closed. To openthe door means are provided accessible from the front of the oven foractuating the sliding element to cause the latch to disengage from thelatch receiving edge.

In the preferred embodiment there is provided a pair of hooked-shapedlatches which engage with a pair of latch receiving edges. Switch meansare provided associated with each of the latch receiving means and eachswitch means is engageable with the latch for actuating the switch whenthe door is closed. The latch receiving means is preferably adjustableby movement of its pivot point which in turn adjusts the position of thelatch receiving edge relative to the latch. Biasing means is also shownin the preferred embodiment for forcing the door to an open positiononce the latch has been disengaged.

BRIEF DESCRIPTION OF THE DRAWINGS Numerous other objects, features andadvantages of the invention should now become apparent upon a reading ofthe following detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a partial front view of amicrowave oven constructed inaccordance with the principles of the present invention and showing themicrowave oven door partially opened;

FIG. 2 is a cut-away side view of the latch assembly of the presentinvention;

FIG. 3 is a rear view of a slightly alternate arrangement to that shownin FIG. 2.

DETAILED DESCRIPTION FIG. I shows a portion of the microwave oven 10including an oven cooking cavity 12, oven door 14, front face wall 16,and front panel 18. The panel 18 may contain controls for the microwaveoven which are not shown in FIG. 1. However, FIG. 1 does show theactuating button 20 of panel 18 which is operable to open the microwaveoven door when it is closed.

For securing the door 14 in a closed position there is provided a latchplate 22 having latches 24 extending therefrom. FIG. 1 also shows theapertures 26 in the front face 16 for receiving the latches 24.

FIG. 2 also shows the latch plate 22 which has the hook-shaped latches24 extending therefrom. The plate 22 may be secured to the door 14 inany suitable manner such as with the use of the rivets 23 shown in FIG.2 or by means of screws. FIG. 2 also shows the actuating button 20 whichcouples by way of shaft 21 to the rear of the front facewall 16 of themicrowave oven.

The major portion of the latch assembly of this invention as shown inFIGS. 2 and 3 is disposed inside the housing of the oven and includes astationary holder 30, a pair of latch receiving means 32, and avertically movable slide bar 34. The slide bar 34 may be actuated forvertical movement at virtually any point therealong. In the embodimentshown in FIG. 2 the slide bar is actuated at the top and in theembodiment shown in FIG. 3 the slide bar may be actuated at either thetop or bottom as discussed in more detail hereinafter.

The stationary holder 30'has a front flange 31 which is secured by aplurality of fasteners 33 or the like to the rear of the front wall 16.The holder 30 may also be secured at other points within the housing ofthe microwave oven. The holder 30 also has a slightly recessed channel38 that extends vertically and accommodates the sliding bar 34.

The latch receiving means 32 comprises a substantially flat holdingplate 40 having a flanged end 42 that terminates in a slanted bearingsurface 44 and edge 46.

The plate 40 is pivoted at point 48 by means of a bolt and nutarrangement. As shown in FIGS. 2 and 3 this bolt and nut arrangementincludes a socket head capscrew 52 that mates with a nut 54 which issecured to a tab member 56 the end of which is locked within recess 57of holder 30. The holder 30 is also provided with an elongated slot 58which permits movement of the pivot point in the direction of thelongitudinal slot. When the pivot point is located properly then thesocket head capscrew can be secured to hold the plate 40 in thatposition yet permitting pivotal movement of the plate 40 relative to thestationary holder 30.

The movement of the plate 40 is provided by employing an intercouplingmember 60 which may be a nut and bolt arrangement which couples betweenplate 40 and an aperture in sliding bar 34. Thus, as the sliding bar 34is caused to move longitudinally in a vertical direction this likewisecauses the plates 40 to pivot therewith. The sliding bar 34, asdepicited in FIG. 3 may be limited in its vertical movement by means ofa post 35 which extends through an aperture in holder 30.

The plate 40 also has secured thereto a switch 62 which has an actuatingbutton 64. The switch is disposed so that the actuating button 64 ispositioned just below the edge 46 a sufficient distance to contact thehook-shaped end of the latch 24 when the latch is engaged with the edge46. The switch 62 may be of conventional design and is shown in thedrawings as including output terminals 66. The switch 62 may beinsulatedly supported from the plate 40 especially if the plate 40 ismetalic.

The slide bar 34 has a top horizontal projection 65 which is normallybiased upwardly by spring 68 but which may be urged downwardly when thedoor is closed to cause downward pivoting of plate 40 to causedisengagement between the latch and edge 46. This operation is providedby a slide bar actuating mechanism which includes actuating button andassociated shaft 21 referred to hereinbefore, support bracket 80, pivotbar 82, common shaft 84, and biasing spring 68. Upon actuation of thebutton 20 the shaft 21 moves rearwardly. The shaft 21 is affixed to thesupport bracket 80 and upon movement of the shaft 21 the bracket 80pivots about shaft 84. Shaft 84 extends through an aperture in thesupporting lip 81, through an aperture in an in-turned flange 83 ofpivot bar 82, through an opposite in-turned edge'of pivot bar edge 82and through an aperture in the holder 30. The second in-turned flange 85of pivot bar 82 contacts the end 65 of the slide bar 34. Normally, thespring 68 has one end 69 which fits under the slide bar end 65 and hasits other end coupled through aperture 71 and about the end of shaft 84to cause an upward biasing of the slide bar 34.

Upon actuation of the button 20 and pivoting of the pivot bar 82, theflange end 85 pivots, as shown in FIG. 2 downwardly against the uppersurface of end 65 to thereby cause a downward pivoting of the bearingsurface 44. Upon sufficient downward movement of a slide bar the latch24 is disengagable from the edge 46.

FIG. 2 also shows a biasing means 86 disposed intermediate the twoplates 40. This biasing means 86 is for biasing the door to an openposition once latch 24 has disengaged from the latch receiving member.For this purpose there is provided a stationary bracket 87 having aflanged end 88 having an aperture therethrough for accommodating slidingplunger rod 90 which has a conical end 91 that is engagable with theactuating button 92 of switch 94. The switch 94 is suitably fastenedpreferably to the stationary holder 30. This switch 94 has electricalcontacts 95 and may be used for controlling operation of certain of thecircuitry associated with the microwave oven. A spring 96 is disposedabout rod 90 and extends between flange 88 and an enlarged retainingflange 97. On the other side of the flange 97 there is an actuatingbutton 98 which is engagable by the door and is pushed inwardly to causethe rod 90 to contact the switch 94 when the door is closed. When thedoor is to be opened and as soon as the latch disengages from the latchreceiving means, the force of the spring 95 is transmitted to member 98which forces the door l4'towards its open position.

PK]. 3 also shows in addition to the top slide bar actuating mechanismalso a bottom mechanism 100 which may be substantially identical to thetop mechanism and includes a support bracket 10], a common shaft 102, abiasing spring 104, and a pivot bar 106. The mechanism 100 operates inthe same manner except that the flange at the end of pivot bar 106 actsupon the top surface 108 of a bottom extension 109 of the slide bar.

One of the important features of the present invention is concerned withthe pivotal latch receiving means and the ease with which this may beadjusted to provide secure latch engagement. This type of an arrangementalso provides a secure latching with a relatively simple construction.Having described one embodiment of the present invention it should nowbe apparent to those skilled in the art that there exists numerous otherembodiments and modifications of the ones disclosed herein, all of whicharecontemplated as falling. within the spirit and scope of the presentinvention.

What is claimed is:

1. A latch assembly for securing a microwave oven door to the face ofthe microwave oven comprising:

means fastened to the cantilevered end of the oven door for securing thedoor to the oven face and including at least one latch,

said face having at least one aperture to receive the latch,

a latch receiving means including means defining an edge for engagementwith the latch when the door is closed,

means for pivotally supporting said latch receiving means with said edgedisposed intermediate the oven face and the pivot point,

a sliding element arranged to move in a generally vertical direction,

means freely securing said latch receiving means to said sliding elementso that as said sliding element moves said latch receiving means isfreeto pivot about the pivot point,

means for biasing the sliding element to a position wherein the latchand latch receiving edge are in engagement when the door is closed andmeans accessible from the front of the oven for actuating the slidingelement to cause the latch to disengage from the latch receiving edge.

2. The latch assembly of claim 1 wherein said means defining an edgeincludes a rearwardly turned lip having a bearing surface over which thelatch is permitted to slide and terminating in the edge.

3. The latch assembly of claim 1 wherein said means for pivotallysupporting said latch receiving means includes a stationary plate and apivot member secured between the plate and latch receiving means.

4. The latch assembly of claim 3 wherein said plate has a longitudinalslot for accommodating the pivot member and permitting adjustment of theedge relative to the latch.

5. The latch assembly of claim 4 wherein the pivot member includes abolt and nut having a tab member to prevent rotation thereof.

6. The latch assembly of claim 1 including an electrical switch havingan actuating means disposed adjacent said edge.

7. The latch assembly of claim 6 wherein the actuating means is disposedjust below said edge.

8. The latch assembly of claim 1 wherein said means for securing thedoor includes a pair of spaced latches. anism having a shaft, and saidmeans for biasing in- 9. The latch assembly of claim 8 including meansfor l d d b uh f forcing the door open when the door is disengaged. c ue s2 1Sprmg lspose a c sha tand comactmg the sliding element.

10. The latch assembly of claim 1 wherein said means for actuating thesliding element includes a pivot mech-

1. A latch assembly for securing a microwave oven door to the face ofthe microwave oven comprising: means fastened to the cantilevered end ofthe oven door for securing the door to the oven face and including atleast one latch, said face having at least one aperture to receive thelatch, a latch receiving means including means defining an edge forengagement with the latch when the door is closed, means for pivotallysupporting said latch receiving means with said edge disposedintermediate the oven face and the pivot point, a sliding elementarranged to move in a generally vertical direction, means freelysecuring said latch receiving means to said sliding element so that assaid sliding element moves said latch receiving means is free to pivotabout the pivot point, means for biasing the sliding element to aposition wherein the latch and latch receiving edge are in engagementwhen the door is closed and means accessible from the front of the ovenfor actuating the sliding element to cause the latch to disengage fromthe latch receiving edge.
 2. The latch assembly of claim 1 wherein saidmeans defining an edge includes a rearwardly turned lip having a bearingsurface over which the latch is permitted to slide and terminating inthe edge.
 3. The latch assembly of claim 1 wherein said means forpivotally supporting said latch receiving means includes a stationaryplate and a pivot member secured between the plate and latch receivingmeans.
 4. The latch assembly of claim 3 wherein said plate has alongitudinal slot for accommodating the pivot member and permittingadjustment of the edge relative to the latch.
 5. The latch assembly ofclaim 4 wherein the pivot member includes a bolt and nut having a tabmember to prevent rotation thereof.
 6. The latch assembly of claim 1including an electrical switch having an actuating means disposedadjacent said edge.
 7. The latch assembly of claim 6 wherein theactuating means is disposed just below said edge.
 8. The latch assemblyof claim 1 wherein said means for securing the door includes a pair ofspaced latches.
 9. The latch assembly of claim 8 including means forforcing the door open when the door is disengaged.
 10. The latchassembly of claim 1 wherein said means for actuating the sliding elementincludes a pivot mechanism having a shaft, and said means for biasingincludes a spring disposed about the shaft and contacting the slidingelement.